The present invention relates to a coil system for coiling of an elongated flexible element, such as a cable, line, rope, hawser, wire or hose, and for uncoiling of the elongated flexible element, in conjunction with which the elongated flexible element is coiled onto a core, which is detachable for the purpose of uncoiling the elongated flexible element by its inner end.
A number of different systems is known for laying optical cables and other types of cables and lines in the ground, and all of these have their advantages and disadvantages. Technical and/or geographical obstacles affect the manner of proceeding with this, and one technical obstacle that can be mentioned is the inability of the equipment to draw, i.e. to feed or blow, the optical cable for the whole of the intended distance. It is then necessary to resort to so-called looping, which is difficult as a rule, especially when long lengths are involved. The majority of projects for which cables are required to be laid in the ground also require looping. There is also a risk of the cable suffering damage if it is left lying above the ground for a long time. The need thus exists for a new coil system which, amongst other things, enables the above-mentioned problem to be solved.
There is also a wish to be able to wind on a certain length of the desired elongated flexible element of the kind referred to above, which is capable of being uncoiled from an intended coil by both internal and external uncoiling and without twinning the elongated flexible element. For example, it must be possible for a length of cable to be uncoiled and drawn out in each of two directions, which are mutually opposite to one another, from a centrally located uncoiling point, without the need to move the coil.
Previously disclosed via JP,A, 53-114083 is a coil system for cables, in which a conically executed core is removable for the purpose of uncoiling the cable by its inner end. An external guard around the wound-on cable coil prevents unwinding of the cable by its outer end. Uncoiling from the inside only is permitted in this way, which requires the use of a machine that rotates the coil and guides the cable as it is uncoiled, so that it does not twist. The core must also be conical, which means that the space available for winging-on the cable is reduced compared with that of a constant core diameter.
Optional uncoiling from the coil is thus not permitted, and in addition special arrangements are required in the case of uncoiling from inside the centre of the coil.
SE-B-469228 relates to the packing of cable inside a case which exhibits a cover and a base, with the cable wound around a shaft. The cable is fed out from the inside via an opening in the cover. Winding-on of the cable takes place around a circular core, which is subsequently removed in conjunction with packing of the coil. Only the packing case with its cover then serve to hold together the resulting cable coil, which excludes the possibility of optional feeding-out of the cable by its internal or external end.
U.S. Pat. No. 4,580,399 describes a coil system in which a cable is wound onto a cylindrical core, in which case uncoiling must take place in a special fashion in an axial direction in order to prevent twisting of the cable. Internal uncoiling requires a conical core, which is drawn out at least for a certain distance before uncoiling from the inside in an axial direction. This arrangement does not permit optional uncoiling from the inside or from the outside of one and the same coil.